Process for recovering fats and oils



United States Patent PROCESS FOR RECOVERING FATS AND OILS Sidney Daniel Chaloner and David McNicoll, Chester, England, assignors of one-third to Hugh Thomas Noble, Cheshire, England; Edith McNicoll, executrix of said David McNicoll, deceased No Drawing. Application March 10, 1951, Serial No. 215,024

Claims priority, application Great Britain March 25, 1950 2 Claims. (Cl. 260-4125) The present invention relates to a process for recovering oils, fats and waxes from spent absorbent material such as fullers earth used in the refining thereof.

The object of the invention is attained by altering the nature of the earthy absorbent material so that it is no longer capable of absorbing oily matter. This alteration is brought about by treating the earthy absorbent material with alkalies or alkali metal salts.

According to the present invention, therefore, earthy absorbent material which has been used in the refining of oils, fats and/or waxes such as fullers earth and consequently contains residual oily matter is treated with an aqueous solution of an alkali or an alkali metal salt. This treatment may be performed in the presence of a detergent which may be added to the mixture or, alternatively, generated in situ by partial hydrolysis of the oily content of the earthy absorbent materials, and this is a preferred form of the invention.

The alkali or alkali metal salt reacts completely with the reactive metallic constituents of the earth. in the case where no detergent is found necessary the complete reaction with the metallic constituents of the earth is sufficient to displace the oil, and where a detergent requires to be used complete reaction prevents ionic detergents from reacting with the earth and so being rendered ineffective.

The ease of liberation of the oil varies with its nature. Non-saponifiable oils of low viscosity such as medicinal paraffin or light lubricating oils may be released to a large extent by treating the earth with an alkali metal salt which exhibits a neutral reaction such as sodium chloride or sodium sulphate; this is especially the case in the presence of a non-ionic detergent. On the other hand such neutral reacting agents are ineffective in the case ofl high viscosity lubricating oils and also of saponifiable 01 s.

The most effective agents are those alkali metal compounds whose aqueous solutions react alkaline towards phenolphthalein and of these sodium carbonate is preferred. Sodium carbonate not only effects rapid disintegration of the earth but at the same time precepitates or neutralizes the reactive ions and so prevents ionic detergents from being precipitated or rendered ineffective.

In a preferred mode of carrying out the process of the present invention, sodium carbonate is added to a boiling mixture of earth and water until a distinct alkalinity to pheuolphthalein persists. The amount varies according to the nature of the earth being treated but is usually less than of anhydrous sodium carbonate calculated on the weight of earth present. Usually no detergent is necessary in the case of recovery of non-saponifiable oils of low Viscosity, but in the case of oils of high viscosity the presence of a detergent is desirable to obtain maximum yields. In the case of fresh earths from the bleaching of neutral saponifiable oils, no oil is liberated, after the reaction with sodium carbonate until a definite amount of soap (as a detergent) has been added or produced by saponification.

The concentration of detergent or soap solution required is generally about 1% (as anhydrous soap) but may be slightly more or less. When it is desired to obtam the required soap by saponification it is necessary to add from 1% to 3% caustic soda (calculated on the earth).

In the case of an earth which contains sufiicient fatty acid or absorbed soap to form a soap solution of the reto emulsification in the more concentrated soap liquor which is formed.

Synthetic detergents may be used, the amounts of these to be employed varying with their nature, but we prefer to use soap as a detergent. The sodium carbonate may be replaced by alkalies such as caustic soda in an amount equivalent to the amount of sodium carbonate necessary to produce alkaline reaction.

When separating non-saponifiable oils a slight excess of the alkali may be employed by adding it directly at C. In the case of saponifiable oils the calculated quantity should be added gradually at about 60 C. until disintegration is complete and in the presence of water in amount from two to four times the weight of earth. Practically no saponification occurs under these conditions and the temperature may then be raised to about 100 C. with gradual additions of alkali to produce sufficient soap to liberate the oil.

In order to obtain uniformly good results it is essential that every particle of the earth should react with the agent. Boiling of the earth with 2-4 times its weight of water is continued with addition of the alkali or alkali metal salt until alkalinity is permanent and all the earth particles are light in colour. The boiling may be effected by steam or by external heat with mechanical agitation. The soap liquor is drawn off from the thick earth sludge and acidified to recover its fatty content. The soap liquors are generally highly coloured and in consequence the recovered oils can be bleached with comparative ease.

The present invention will be further understood by reference to the following examples in which all quantities are parts by weight.

Example I.-100 parts of earth containing a low viscosity lubricating oil were boiled with 200 parts of water and 8 parts of anhydrous sodium carbonate until disintegration was complete and alkalinity to phenolphthalein persisted.

On allowing to settle separation of oil was almost instantaneous and about 3% oil remained in the earth, calculated on dry weight.

Example II.-100 parts of earth containing viscous lubricating oil were boiled with 200 parts of Water and 8 parts of anhydrous sodium carbonate as in Example I. Separation of oil was slow and incomplete. On the addition of about 0.1% of an anhydrous ester salt detergent from petroleum, the separation of oil became rapid and only;l 5% (calculated on dry weight) remained in the cart Example IlI.100 parts of earth from bleaching of tallow were boiled with 300 parts of water and 8 parts of anhydrous sodium carbonate. The presence of 3% free fatty acid in the earth produced suflicient soap to act as an efficient detergent when slight alkalinity to phenolphthalein persisted. Separation of the oil was rapid. 2% fatty matter was present in the soap and 33% of the total weight of spent earth was recovered as fat.

Example I V.-100 parts of earth from the bleaching of neutral lard were boiled as in Example I. No oil was liberated until after the addition of 2% soap (calculated as fatty acid). The earth, after Washing, was free from oil.

Example V.l00 parts of earth containing neutral cod liver oil were boiled with 300 parts of Water and 7 parts of anhydrous sodium carbonate. No oil Was liberated, but on gradually adding about 2% caustic soda all the oil rose to the surface within a few minutes. The soap liquor formed by partial hydrolysis of the oil by the caustic soda contained 2% fatty matter, and the earth, after washing was oil free.

Example VI.100 parts of earth containing neutral rape oil were heated with 300 parts of water and 6 parts of caustic soda at 60 C. The earth was completely disintegrated but the oil was not ompletely liberated until after raising the mixture to boiling and gradually adding 2 parts of caustic soda. The soap liquor formed contained 3%. fatty matter and the earth, after washing, was oil free.

We claim:

1. A process of recovering oils, fats and waxes from earthy absorbent materials used in refining said oils, fats and waxes which consists in heating said earthy absorbent material with an aqueous solution of sodium hydroxide in an amount sufiicient to neutralize the earthy absorbent and in the presence of a detergent, in which the calculated quantity of sodium hydroxide required to react completely with the earthy absorbent material is added to a mixture of said earthy absorbent material and water in amount equal to 2 to 4 times the Weight of said earthy absorbent material at 60 C., agitating, and, after disintegration of the earthy absorbent material, a further quantity of sodium hydroxide sufficient to produce the necessary soap to cause separation of the oil is added while the temperature is raised to 100 C., and removing said oils, fats and Waxes from the mixture.

2. A process of recovering oils, fats and waxes from earthy absorbent materials used in refining said oils, fats and waxes which consists in heating said earthy absorbent material with an aqueous solution containing less than 10% (calculated on the Weight of earthy absorbent material) of a member of the group which consists of alkalis, alkali metal salts Which react alkaline to phenolphthalein and mixtures of alkilis and alkali metal salts which react alkaline to phenolphthalein in amount sufiicient to neutralize the earthy absorbent at 60 C. and in the presence of a detergent while the temperature is raised to 100 C. and removing the separated oils, fats and waxes from the mixture.

References Cited in the file of this patent UNITED STATES PATENTS 1,070,435 Felizat Aug. 19, 1913 1,763,167 Lowery June 10, 1930 2,117,223 Slocum May 10, 1938 2,279,408 McDonald Apr. 14, 1942 

1. A PROCESS OF RECOVERING OIL, FATS AND WAXES FROM EARTHLY ABSORBENT MATERIALS USED IN REFINING SAID OILS, FATS AND WAXES WHICH CONSISTS IN HEATING SAID EARTHY ABSORBENT MATERIAL WITH AN AQUEOUS SOLUTION OF SODIUM HYDROXIDE IN AN AMOUNT SUFFICIENT TO NEUTRALIZE THE EARTHLY ABSORBENT AND IN THE PRESENCE OF A DETERGENT, IN WHICH THE CALCULATED QUANTITY OF SODIUM HYDROXIDE REQUIRED TO REACT COMPLETELY WITH THE EARTHLY ABSORBENT MATERIAL IS ADDED TO A MIXTURE OF SAID EARTHLY ABSORBENT MATERIAL AND WATER IN AMOUNT EQUAL TO 2 TO 4 TIMES THE WEIGHT OF SAID EARTHY ABSORBENT MATERIAL AT 60* C., AGITATING, AND, AFTER DISINTEGRATION OF THE EARTHLY ABSORBENT MATERIAL, A FURTHER QUANTITY OF SODIUM HYDROXIDE SUFFICIENT TO PRODUCE THE NECESSARY SOAP TO CAUSE SEPARATION OF THE OIL IS ADDED WHILE THE TEMPERATURE IS RAISED TO 100* C., AND REMOVING SAID OILS, FATS AND WAXES FROM THE MIXTURE. 